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Complex Fertilisers

These include nitrogen-phosphatc-potassium fertilising materials such as
stable manure and other excrements, gun-no, dried blood, meat waste, silkworm
chrysalides, residues of wool, hair, Jcallicrs, leather, horn, nails, etc., oleaginous
seed cake, peat, various industrial residues and artificial mixtures of mineral
or organic and mineral fertilisers.

Analysis of these products comprises essentially determinations of the
moisture, nitrogen, total phosphoric acid and potash, these being carried
out by the general methods already described with only such modifications
as are indicated below.


The sample should be taken from many points of the mass and should
be mixed without pressing it so as to lose- none of the liquid portion.

Analysis is made partly on the product previously dried at 80" and partly
on the fresh product.

1.  Water.—250-500 grams are dried at 70 80" for sonie^ hours and then
left to cool in the air and weighed.    The dried mass is then cut into small
portions, chopped and reduced to a, fine powder, which is thoroughly mixed
again.    10 grams of this are then heated at 105" until o[ constant weight,
the total moisture being calculated.

In order to avoid any loss of ammonia, the total water may be deter-
mined as indicated in General Methods, 2.

2.  Ash.—20 grams of substance dried at 80" and powdered, as in i, are
incinerated at a dull red heat.

3.  Phosphoric Acid and Potash.   These are determined in the ash;
sec. General Methods, 4 and 5.

4.  Nitrogen.- -The ammoniacal nitrogen is determined on the fresh
manure, 100 grams of which are distilled with magnesium oxide ; the nitric
nitrogen by protracted digestion of 500 grams with water, the liquid being
subsequently made up to volume and the nitrogen in an aliquot part of the
filtrate, corresponding with at least 100 grams of substance, determined by
the Sclmlze and Tiernann method ;   the. total nitrogen, by the IJlsch (or
Jodlbaur, if nitrates are present) modification of Kjeldahl's method, on
loo grams of substance previously treated with 200 c.c. of phosphosulphnric
acid in the manner described in  the,  following  article:   Other  complex
fertilisers, 2.

In each case the procedure is as proscribed under General Methods, 3, A,
B, and D.

The composition of stable manure varies, in the majority of cases, between
the following limits (%) : water, do-80 ; ash, 5-13 (more frequently, 10-14);
total nitrogen, 0-3 -o-H, small proportions only being in the anituoniacal condition
and very little or none in the nitric state, if the manure is well preserved ; phos-
phoric anhydride, o-2--0'5 ; and potash, o^-i (usually 0-5•<>•<>).42.